CVE-2021-39509 (GCVE-0-2021-39509)

Vulnerability from cvelistv5 – Published: 2021-08-24 18:52 – Updated: 2024-08-04 02:06
VLAI Previdian
Summary
An issue was discovered in D-Link DIR-816 DIR-816A2_FWv1.10CNB05_R1B011D88210 The HTTP request parameter is used in the handler function of /goform/form2userconfig.cgi route, which can construct the user name string to delete the user function. This can lead to command injection through shell metacharacters.
Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE
  • n/a
Assigner
References
Previdian
Known Exploited Vulnerability - GCVE BCP-07 Compliant
KEV entry ID: 79b36802-2886-43c3-967a-9230feedbcde

Vulnerability ID: CVE-2021-39509

Status: Confirmed

Status Updated: 2021-08-24 20:52 CEST

Exploited: Yes

Timestamps
First Seen: 2021-08-24
Asserted: 2021-08-24
Scope
Notes: An issue was discovered in D-Link DIR-816 DIR-816A2_FWv1.10CNB05_R1B011D88210 The HTTP request parameter is used in the handler function of... | Affected: D-Link / DIR-816 | CVSS: 9.8 (CRITICAL) | EPSS: 0.05098 | Used in malware: unknown | Not yet in CISA KEV: True
Evidence

Type: Public Report

Signal: Successful Exploitation

Confidence: 70%

Source: previdian

Details
Feed Previdian (previdian.com)
Title An issue was discovered in D-Link DIR-816 DIR-816A2_FWv1.10CNB05_R1B011D88210 The HTTP request parameter is used in the handler function of...
Cve Id CVE-2021-39509
Vendor D-Link
Ghsa Id None
Product DIR-816
Added Date 2021-08-24T18:52:26.000Z
Cvss Score 9.8
Epss Score 0.05098
Previous Ids
Cvss Severity CRITICAL
Virtual Patch False
Cvss Estimated False
Epss Percentile 0.92097
Used In Malware unknown
Vulnerability Id CVE-2021-39509
Ahead Of Cisa Kev None
Not Yet In Cisa Kev True
References
Created: 2026-10-02 09:11 CEST | Updated: 2026-10-02 09:11 CEST
Show details on NVD website
To clipboard 

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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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